Vanishing Peanuts
Age
Elementary School, Middle School, High School
Format
Stage Show, Hands-on
Materials
Box of styrofoam packing peanuts Handful of cornstarch packing peanuts 2 Jars with lids filled halfway with water Large Glass bowl or Beaker Acetone Any type of styrofoam
Safety Precautions
Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience. If asking for any volunteers, watch them carefully while around the acetone. Be careful of splashing while pouring the styrofoam packing peanuts into the acetone.
Preparation
Fill the two jars halfway with water.
Fill the glass bowl/beaker a quarter to a halfway full of the acetone.
Demonstration
First use the two jars of water. Show the students the styrofoam packing peanuts and ask them what will happen when placed in water. After receiving answers, drop the peanuts into the jar until it is filled. Screw on the lid and shake it. Nothing will happen. Next, take the cornstarch peanuts and ask the students what will happen if you place them in water. You can ask for a volunteer to help you, if you wish. After receiving answers, fill the jar with the cornstarch peanuts until it is full and screw on the lid. Shake it (or let the volunteer do it) and the cornstarch peanuts will dissolve.
The next part involves the acetone. Grab the box of styrofoam peanuts. Ask the students what they think will happen. Then ask them how many peanuts they think it will take to fill up the bowl/beaker. Take some numbers. Then, carefully pour the peanuts into the bowl/beaker. It will seem that they vanish right in front of your eyes! The entire box should fit into the beaker. If you have any other pieces of styrofoam, feel free to add them to the bowl/beaker or let some of the students do it (but keep a close eye on them! make them wear gloves and goggles!)
NOTE
The polystyrene left at the bottom of the container is moldable. When the acetone dries up, you can feel free to mold the substance into various shapes if you want.
What to Say
Styrofoam is one of the most popular products used for packaging and shipping. It is used all over the world, but nearly 200 million cubic feet is used in the United States alone. Today, let's take a look at just what would happen if we placed these regular Styrofoam packing peanuts into some water. Next to it, I'm going to use these special cornstarch packing peanuts and see what happens between the two of them. Would a volunteer like to help me? Alright, I'll shake mine while you shake yours. Let's see what happens. *shake jars* Nothing has happened to mine. What about yours? Oh wow, it's gone! What was the difference between the two of them? Anyone have any ideas? Styrofoam is not biodegradable, meaning that it will not break down in water and it will sit in landfills for many many years! These cornstarch peanuts, on the other hand, will dissolve easily in water and naturally decompose in landfills. So when reaching for some peanuts to protect the lamp you want to ship to your mom, either reuse the Styrofoam peanuts, or use these new cornstarch ones. Try not to throw away Styrofoam. It is tempting because it is difficult to recycle these days. Just remember, reuse, reuse, reuse.
On that topic, since the Styrofoam did not decompose in the water, how will it be broken down? Here I have a bowl filled with a special chemical. Here, I have an entire box of Styrofoam packing peanuts. What do you think will happen? How many peanuts do you think I'll be able to fit into this bowl/beaker? Let's make it a mini competition. *take down some numbers* Alright, let's take a look what happens. ..... Did anyone guess the entire box?! How about if I take a normal stick of styrofoam, what will happen to that? .... Hey, it's gone too! What this is showing is that Styrofoam has very little actual material to it. 95% of all Styrofoam products is really just air. No wonder it fills up our boxes and landfills so quickly! If anyone would like to come down and make some styrofoam vanish themselves, feel free to come do so. But the moral of this story is, Styrofoam is one of our biggest concerns environmentally. It used so broadly and so carelessly that our landfills will be full before you know it. So please, reuse any Styrofoam you have. Tell your friends to do the same. And start using replacements for the Styrofoam, such as these cornstarch packing peanuts I showed you. Small steps will lead us to a greener, healthier environment and it's up to you guys to bring it there!!
Why It Is
Styrofoam is made out of polystyrene and air. Air makes up about 95% of it though. When polystyrene is combined with acetone, the material breaks up and releases all of the air. That is why it looks like the packing peanuts are basically "vanishing". Very little is left of them and it sinks to the bottom of the container. The material left at the bottom of the container is solid polystyrene.
Real Life Examples
It is very similar to dissolving something like Alka seltzer in water. The actual tablet dissolves to produce Carbon Dioxide gas, making it look like the tablet is basically disappearing by dissolving the ingredients into the water.